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@dlwh
function accumulate(denseVector) is equivalent to MATLAB cumsum().
perhaps that name is better, and we should change it---although I've never quite liked the sound of it.

Also, I tried out the recursive list construct for implimentation, there might be a better way to do it, but I was having trouble with @expand ing when I tried to use tabulate/loop-type construct with cumulator variable.

Kenta